Control device



April 1, 1952 H. A. MUDD 2,591,184

CONTROL DEVICE Filed June 24, 1949 Al uuuuu I j w A [WENTOR HfiR/TY A, M1100 BY ATTORIVEY for that valve.

drw batteries.

Patented Apr. 1, 1952 ooNTRoL DEVICE Harry A. Mudd, ltlaplewood, Mo., assignor to McQuay-Norris Manufacturing Company, St. Louis, Mo., a corporation of Delaware Application June 24, 1949, Serial No. 131,076

6 Claims.

This invention relates to improvements in control devices. More particularly this invention relates to an improved control device that is readily'effected by providing a valve in the fuel line of thatiengine and by providing an actuator The actuator is preferably electrically operated, and it. preferably draws currentonly when it actuates the valve. The present invention. provides such as actuator by making a solenoid with a plunger of considerable magnetic retentivity and with a coil that-has a magnetizing. section and. a tie-magnetizing section. The plunger of considerable magnetic retentivity willv respond to energization of the magnetizing section of the coil to move into valve-closing position andits magneticretentivity will enable itstocoact with the residual magnetism of the coil to maintain: itself in valve-closing position indefinitely; As a result. only. a momentary energization of the magnetizing. section of the coil is needed to move the plunger to valveclosing. position and to cause. it to remain in that position; and'this minimizes current consumption. Return of the-plunger-to valve-opening position is' effected by passing a current through the ale-magnetizing. section of the coil for ashortperiod of time," thereby reducing the residual. magnetism of the coil and plunger to values-atwhich a springcan move the plunger. Again, current. consumption is minimized since only a momentary passage of. current through the de-magnetizing section of the coil is needed to reduce the residualmagnetism". It is therefore-an object of-the present invention to provide asolenoid with a plunger having considerable magnetic retentivity and a coil having a magnetizing section and a de-magnetizing section.

The passage of current through the magnetizing and de-magnetizing sections of the coil of the solenoid is best controlled by. normally-open push button switches. Where such switches are used; the currentnow will cease as soon as the push buttons are released; and under'such conditions the current can easily be provided by It is; therefore'an object of the present invention to provide push button switches that control the flow-of current through the magnetizing and de-magnetizing sections of the solenoid coil.

The solenoid provided by the present invention can also protect the internal combustion engine against injury due to failure of the lubricating or cooling systems of that engine. This is done by providing a pressure-responsive switch that responds to variations in the pressure in the lubricating system of the engine, and by providing a temperature-1esponsive switch that responds to variations in the temperatures within the cooling system of the engine; and by having those switohesenergize the magnetizing section of the solenoid coil when the oil pressure decreases unduly or when the coolant temperature increases unduly. It is therefore an object of the present invention to provide a pressure-responsive switch and a temperature-responsive switch that selectively energize the magnetizing section of the coil of a solenoid.

When an internal combustion engine starts to operate, the pressure within the lubricating system of that engine willbegin torise, but that pressure may not immediately rise to normal operating levels. for short periods withless-than-normal pressures in the lubricating system, but it cannot do so indefinitely. It is therefore'desirable to permit the engine to run for short periods of time even though the pressures in the lubricating system are abnormally low, but to stop the engine if the low pressure'continues. The present invention makesthis possible by providingv a thermostatic switch in series with the magnetizing section of the solenoid coil and by providing a heating, element in series with the pressure-responsive switch. The time required for the heating element to actuate the thermostatic switch will be long enough to enable the pressures inthe lubricating system of the-engine to rise to normal values if operating conditions are normal but will be short enough tocause energization of the magnetizing section of the coil, With'consequent closing of the valve in the fuel line, ii'the pressure in the lubricatingsystem of the engine continues to be abnormally low. It is therefore anobject of the present invention to provide a thermostatic switch in series with the magnetizing section of a' solenoid coil and to provide a heating element, adjacent that switch, in series with. a pressure-responsive switch.

Other and further objects and advantages of the. present invention should become apparent The engine can operate safely from an examination of the drawing and accompanying description.

In the drawing and accompanying description a preferred embodiment of the present invention is shown and described but it is to be understood that the drawing and accompanying description are for the purposes of illustration only and do not limit the invention and that the invention will be defined by the appended claims.

The accompanying drawing is a schematic diagram or a solenoid with a plunger having considerable magnetic retentitivity, and of the control circuit associated with that solenoid.

Referring to the drawing in detail, the numeral ll) denotes the fuel line of an engine which can be stopped by halting the flow of fuel to it. A valve I2 is provided in the fuel line It, and that valve can be rotated in a counter-clockwise direction until it permits fuel to pass through line I to the engine; or it can be rotated to the position shown in the drawing to prevent fuel passing to that engine. The valve i2 is mounted on a shaft M which is pivotally supported within the fuel line Ill; and a portion of that shaft extends outwardly beyond the fuel line H) and supports a crank arm I 5. A lever F8 is loosely pivoted to the end of crank arm I 5, as by having an elongated hole or slot in the end of that lever; and that lever is also pivoted to a fulcrum IS. A tension spring I! is connected to the le- -ver l6, and that spring tends to rotate that lever in a clockwise direction. Such rotation opens the valve l2 by rotating the crank arm [5 in a counter-clockwise direction. Relative movement of lever t6 and crank arm I5 is possible, despite the fact that pivots M and I8 are fixed, because of the loose connection between the lever I6 and crank arm l5.

The other end of lever arm l6 projects beyond fulcrum I8, and that end will be selectively engaged by the plunger of a solenoid. This plunger will preferably be made of high carbon iron or steel and will have considerable magnetic retentivity. Plunger 20 is disposed axially Within de-magnetizing section 28 and magnetizing section 30 of the solenoid coil; and it will be biased for upward movement by a compression spring 24 that extends between a stationary frame element 22 and a collar 26 mounted on the plunger 29. The plunger 20 will respond to the "lines of force generated in the magnetizing section' 39 to move downwardly to the position shown in the drawing, thereby opening switch 44 and closing valve I2. That plunger will remain indefinitely in the position shown in the drawing because of the conjoint effect of the retentivity of the plunger and the residual magnetism in the coil. When, however, the residual -magnetism in the coil is reduced, as by passing a current through the de-magnetizing section 28, the plunger 22] will move upwardly in response to spring 24 and will close switch 44 while permitting valve E2 to open.

1 The de-magnetizing section 28 of the solenoid coil will have fewer ampere turns than the magnetizing section 3; thus the section 28 will be unable to move the plunger 20 downwardly against the force of the spring 24. Instead the section 28 will only be able to reduce the residual magnetism in the solenoid coil to values at which the spring 24 can move the plunger 20.

The adjacent ends of the sections 28 and 30 of the solenoid coil are connected together and are connected to ground. The outer end of sec- ,tion 28 is connected to one terminal of a battery 38 by conductor to, push button 32, junction 36, conductor 3'5, and junction 56. The outer end of section 3t is connected to that terminal of the battery 33 by conductor l2, junction 58, push button 3' 3, junction 36, conductor 3?, and junction 55. is connected to ground, and thus when one or the other of the push buttons 32 and 34 is pressed, a circuit is completed through one or the other of the sections of the solenoid coil; the section 28 being energized when push button 32 is pressed, and the section 3% being energized when push button 34 is pressed. The circuits [through the sections 28 and 3B will be completed only as long as the push buttons 32 and 3d are pressed down, and as soon as the forces on those push buttons are released, those circuits will be opened.

The armature of the switch id is secured to the upper end of the plunger 2, and that armature spans the two spaced contacts of that switch. The switch at is disposed between the battery 38 and a heating element 46; andthat heating element is selectively connected to ground by a pressure-responsive switch 50' or-a temperature-responsive switch 52. The pressureresponsive switch 59 is closed whenever the pressure in the lubricating system of the engine is below a predetermined value, but that switch will open whenever that pressure reaches that value. The predetermined value is set so the switch50 will be held open when the engine is operating normally, but will be closed when that engine is not operating or is not operating properly. The switch 52 is a temperature-responsive switch that responds to the temperature of the coolant in the engine, or tothe temperature of the engine itself; and it is normally in open position. When the temperature or? the coolant or of the engine itself rises above a predetermined level, the switch 52 will close.

When either of the switches 56 or 52 closes, at a time when the switch 54 is closed, a circuit will be completed from battery 38, through switch 44, through heating element it, .and through one of those switches to ground; As a result, current will flow through the heating element 46, 'and that current will generate heat in the heating element 4 5. That heat will affect the thermostatic switch 5 3; and if the current through the heating element 45 continues for an appreciable period of time, as for example sixty (60) seconds, the thermostatic switch 5 3 will close. Theiclosing of the switch 54 will complete a circuit fromth'e battery 33, through junction 56, throughswitch 54, through junction 58, through conductor, and through the magnetizing section 30 of the solenoid coil to ground; and this will cause the plunger 26 to move downwardly and open the switch it while closing the valve'lZ, If the current through the heating element 46' continues only for a shorter period, as when the oil pressure is below the predetermined value for a few seconds or when the temperature of-the coolant or the engine itself rises above the predetermined level for a few secondathe heat fromthe heating element it will be insufilcient to close the thermostatic switch 56. In the latter cases, the engine can continue to operate without interruption. As a result, the control device provided by the present invention avoids needless interruptions due to harmless, short-duration transitory changes in oil pressure and coolant temperature,

but will halt the engine long before any injury The other terminal of the battery 38 tion does this without imposing a steady drain on the battery 38; current being drawn from that battery only when the engine is started and stopped, when the oil pressure is too low, or when the coolant temperature is too high. Thisis accomplished by having the push buttons 32 and 34 biasedto open position,- and by having-the thermostatic switch 54 open except when the oil pressure is too low or the coolant temperature is too high,

The normal position of the plunger 20 is shown in the drawing; and that plunger'is held inthat position, against the biasing force of spring 24, by the coaction of the magnetic retentivity of that plunger and the residual magnetism of the coil. In that position, the plunger 2c holds valve l2 closed and holds switch 44 open; and no current \vill'be drawn from the battery 38 since push buttons 32 and 34, as well as switch A l, are open. The plunger 20 can remain in this position indefinitely, thus avoiding all current drain from the battery during off periods of the engine. Vihen the engine is to be started, the start push button 32 is momentarily pressed; and this completes a circuit from battery 38, through junction 55, junction 36, switch 32, conduct-or 43, and demagnetizing section 26 to ground. Although this circuit will only be completed momentarily, the push button 32 opening that circuit as soon as it is released, sufiicient current will flow through thede-magnetizing section 28 to reduce the residual magnetism of the solenoidL coil to a value at which it cannot overcome the force of spring 25. Thereupon the plunger will move upwardly to close switch 44 and to permit spring i! to open valve 12.

The opening of valve I2 will permit fuel to how through the fuel line H) to the engine, and the closing of switch 4 1 will permit current to how through the heating element 36 because the pressure-responsive switch to will be closed. The heat from the heating element 48 will cause the thermostatic switch 54 to tend to move to closed position; but under normal operating conditions the pressure in the lubricating system of the engine will quickly rise to the value at which the switch 50 opens, and it will usually reach that value and open switch 50 before thermostatic switch 54 closes. Opening of the switch 50 will halt further flow of current through the heating element 45, and the thermostatic switch 54 will cool down and remain open.

The plunger 20 will remain in its upper position, under the action of spring 2 1, as long as the engine operates normally or as long as the stop push button 34 is not pressed; and it will remain in that position even if the pressure-responsive switch 50 or the temperature-responsive switch 52 closes for short periods of time. When, however, the engine fails to operate properly and the pressure-responsive switch 58 or the temperatureresponsive switch 52 closes for more than a minute, or when the stop push button 34 is pressed, the plunger 20 will be actuated by the magnetizing section 30 of the solenoid coil. In case the pressure-responsive switch 58 closes, a circuit will be completed from battery 33, through switch 4 1, heating element 4%, junction 48, and switch 50 to ground. The closing of that circuit will cause thermostatic switch 54 to close; and that will complete a circuit from battery 38, through junction 56, switch 54, junction 58, conductor 42 and magnetizing section 39 to ground. The closing of this latter circuit energizes the magnetizing section 30 of the coil; and the consequent movement of plunger 20 will open switch MLw-hile closing valve l2. The engine will continue to run for a few-minutes but will soon stop for lack of fuel. In case the temperature-responsive switch 52 closes, the circuit through the heating element 46 will be completed through switch, 52 rather than switch 58, but the-circuit through the thermostatic switch 54 will be completed in the same way. In case the stop, push button 34 is pressed, a circuit will be completed from the battery 38, through junction :56, conductor 31, switch 34, junction 58, conductor 42, and section 3!} to ground.

In each case, the plunger!!! will move to the position shown in the;drawing and willbe held there by the, coaction of its magnetic retentivity and the residual magnetism of the solenoid coil. In that position of plunger 20,- theswitch Mlwill be open and it will open the-circuit through the heating element 46; and this permits thev thermostatic switch 54 to cool and open the circuit through the section 30 of the solenoid coil. From this it is apparent that in either of the two positions to which plunger 20 can move, no current is drawn from battery 38 until one of the switches 32, 34, 56, or 52 is closed.

The de-magnetizing section 28 of the solenoid coil is wound in such a manner that it draws considerably more current than the heating element 46 or the magnetizing section 30 draw. This is a very important safety featuresinceiit guarantees that if the battery 38 has enough electrical capacity to open valve l2, as byde-magnetizing the coil to permit the plunger-20 to move upwardly, that battery will have enough capacity to heat the heating element 46 and close thermostatic switch 54, and then to energize section 30 of the solenoid coil.

Whereas a preferred embodiment of themesent invention has been shown and described in the drawing and accompanying description it should be obvious to those skilled in the art that various changes may be made in the form of the invention without aiiecting the scope thereof.

What I claim is:

1. A control device that comprises a solenoid coil, a solenoid plunger, said solenoid coil having a magnetizing section which can respond to momentary energization to move said solenoid plunger to energized position and to create a residual magnetism within said solenoid coil and a de-magnetizing section which can respond to momentary energization to reduce the residual magnetism within said solenoid coil, said solenoid plunger having sufficient magnetic retentivity to coact with residual magnetism in said coil to hold itself in magnetized position, a spring biasing said plunger out of magnetized position, a switch that is operated by said plunger and is in series relation with a heating element and with a condition-responsive switch, a normally open thermostatic switch that is adjacent said heating element and is in series relation with said magnetizing section of said coil, a normally open starting switch in series with said de-magnetizing section of said coil, and a normally-open stopping switch in series with said magnetizing section of said coil, said starting switch being closable to momentarily energize said de-magnetizing section of said coil so said spring can move said plunger to de-magnetized position and close said plunger-operated switch, said condition-responsive switch normally being open when said plunger is in tie-magnetized position but being closable to energize said heating element and cause said thermostatic switch to close the circuit of said magnetizing section of said solenoid coil, said stopping switch being closable to momentarily energize said magnetizing section of said coil and move said plunger to magnetized position and open said plunger switch.

2. A control device that comprises a solenoid coil with two sections, a solenoid plunger selectively movable in response to energization of said sections, and a heating coil controlling a thermostatic switch, said thermostatic switch being in series with one of said sections of said solenoid coil, said one section of said solenoid coil and said heating coil having less resistance than the other section of said solenoid coil. whereby a source of electricity having sufficient capacity to energize the other of said sections of said solenoid coil will have sufiicient capacity to 'energize said one section of said solenoid coil and said heating coil.

3. A control device that comprises a solenoid plunger, a solenoid coil, a switch that is in series relation with said coil, a second switch that is in series with said coil but is in parallel relation with said first switch, said first switch being a manual switch, said second. switch being a thermostatic switch, and a condition-responsive switch that is in series with a heating element, said heating element being adjacent to and in heat-transferring relation with said second switch, sponding to a predetermined condition to energize said heating element and thereby cause heating of said second switch, said second switch responding to said heating to close the circuit to said coil.

4. A control device that comprises a solenoid plunger, a solenoid coil, a switch that is in series relation with said coil, a second switch that is in series with said coil but is in parallel relation with said first switch, said first switch being a manual switch, said second switch being a thermostatic switch, a switch that is actuated by said plunger, and a condition-responsive switch that is in series with said plunger-actuated switch and with a heating element, said heating element being adjacent to and in heat-transferring relation with said second switch, said plunger acting in a predetermined position to close said -plunger-actuated switch so closure of said condisaid condition-responding switch re-,

tion responsive switch can energize said heating element. i

5. A control device that comprises a solenoid coil, a solenoid plunger with sufficient magnetic retentivity to coact with residual magnetism in said coil to hold itself in magnetized position, a plunger-operated switch, a heating element, a condition-responsive switch, said plunger-open ated switch and said heating element and said condition-responsive switch being in series, and a thermostatic switch that is in series with said solenoid coil and responds to changes in-the heat from said heating element to energizesaid solenoid coil, said plunger-operated switch permitting energization of said solenoid coil when said condition-responsive switch is closed for a time sufiicient to cause the heating element to actuate said thermostatic switch, said condition-responsive switch and said heating element and said thermostatic switch. energizing said solenoid coil whenever a dangerous condition continues for an undue period of time.

6. Control apparatus that comprises a solenoid coil with a magnetizing section and a de-magnetizing section, and a plunger movable in response to energization of said sections, a therinostatic switch in series with said magnetizing section of said coil, a heating element adjacent to and in heat-transferring relation with said thermostatic switch, and a switch in series with said heating element to selectively initiate energization of said heating element, and thereby cause heating of said thermostatic switch, said thermostatic switch responding to said heating to close the circuit to said magnetizing section of said coil, said de-magnetizing section of said coil requiring more current than said magnetizing section and said heating element draw.

HARRY A. MUDD.

REFERENCES GITED The following references are of record in the file of this patent:

Sherwood Mar. 1, 1949 

